Make and receive RTT calls on your iPhone

With iOS 11.2 or later, you can now use the RTT (real-time text) protocol for conversational text calls.

Set up RTT

This feature is available on iPhone 6 and later with carrier plans from Verizon, AT&T, and T-Mobile.* Standard voice call rates apply for RTT calls.

Here's how to set up RTT:

Go to Settings > General > Accessibility > RTT/TTY.

Turn on Software RTT/TTY. In the status bar at the top of your screen, you should see .

Tap Relay Number and enter a phone number for TTY relay calls.

You can also change these settings:

To send characters as you type them, turn on Send Immediately. Or, to type full messages before you send, turn off Send Immediately.

To answer every call as TTY, turn on Answer All Calls as TTY. If you turn on Answer All Calls as TTY, you won't get voice calls anymore. Even if you turn on Answer All Calls as TTY, you can still upgrade any calls that you get by using the RTT button.

To answer and make TTY calls from an external TTY device instead of your iPhone, turn on Hardware TTY. Make sure that you also turn on Answer All Calls as TTY.

After you set up your iPhone, you can make and answer RTT calls, or upgrade a voice call to RTT.

* RTT and TTY aren’t supported by all carriers or in all regions. RTT and TTY functionality depends on your carrier and network environment. When making an emergency call in the U.S., iPhone sends special characters or tones to alert the operator. The operator’s ability to receive or respond to these tones can vary depending on your location. Apple doesn’t guarantee that the operator will be able to receive or respond to an RTT or TTY call.

Place an RTT call

Open the Phone app.

Select your contact and tap their phone number.

Select RTT/TTY Call or RTT/TTY Relay Call.

Wait for the call to connect, then select RTT .

Enter your message.

If you turn on Send Immediately in Settings, your recipient sees your message as you type.

If not, enter your message, then tap to send.

Want to find shortcut phrases? Wait a moment before you type your message and shortcuts appear, like SK for "ready to hang up" and GA for "go ahead."

Upgrade a voice call to RTT

Open the Phone app.

Select the contact and tap their phone number. To upgrade to RTT during the voice call, tap Use RTT to the right of .

Wait for Mute to change to RTT .

Tap RTT to open the text conversation.

Voice calls upgraded to RTT will always keep the microphone active, tap in the top-right to turn off audio for the call.

To end an RTT call

Tap Back.

Tap .

Answer an RTT call

With RTT/TTY enabled, appears instead of the Answer button

Tap Accept to answer the call.

Then tap RTT to upgrade the call to a text conversation.

If you haven't set up RTT/TTY, you can still answer a call and upgrade to RTT. When the RTT call comes into your phone, you'll see this message: "RTT allows text messages to be sent during a phone call between recipients. This service is typically used by those with hearing impairments. Press the RTT button to communicate using text with the caller." Tap Got It to accept the RTT call.

Learn more

RTT also allows you to combine voice and text calls. Both incoming and outgoing calls that start as voice, then upgrade to RTT will keep the microphone active. The microphone in the top-right of the text conversation will be blue when the microphone is on and voice audio is active. Tap to turn off voice audio for any RTT upgraded call. If you started a call as RTT and voice audio is off, you can tap to activate it.